Question

19) If one zero of the quadratic polynomial x² + 3x + k is 2, then the value of k is
(A) 10
(B)-10
(C) 5
(D) -5​

Answer 1

Given:

1) x²+3x+k=0...... (Quadratic equation)

2) 2 is the root of a given quadratic equation.

To Find:

k=?

Solution:

Put x=2 in the equation.

So, x²+3x+k=0

(2) ²+3(2) +k=0

4+6+k=0

10+k=0

k=-10

So the value of k is -10. (Option B.)